Difference between Opus BT-C3400 & BT-C3100 v2.1?

The BT-C3400 will charge 'C' batteries and the BT-C3100 will not.

Welcome to BLF,
Sorry this being your first post and all, but……

The charger has a standard 12V DC connector. You can just buy a 12V AC adapter with the desired line cord/plug as long as it can output at least 3 amps at 12V. Because of the issues on the V2.0, I actually use a 6 amp AC adapter, and that solves the problems that v2.1 fixed. The problem is that the charger basically uses PWM to charge, so during the charge cycle the peak current is a lot more than the average current, and the original 3 amp supply didn’t have enough output to provide the peak current required. A larger power supply solves that problem.

So, in your opinion, what is the real difference between the 3100 and the 3400 other than a number on the product?



Hmmm? OK, but do you have any specs from an operation manual to show that the 3100 works with 'C' batteries? All the specs I have read on the 3100 do not list 'C' batteries as being compatible, but they list 'C' batteries in the specs of the 3400 as being compatible.

Nevertheless, do you have a pic showing real capacity with mAh with the exact same batteries in the test mode?

I think the question here is that if the 3100 was apparently not designed to work with 'C' batteries but does appear to be working with 'C' batteries, is it really working properly with 'C' batteries?

I'd love to see a pic with those same exact 2000 mAh batteries showing the mAh real capacity in the test mode. This would be very convincing that the 3100 works properly with 'C' batteries even though it wasn't apparently designed to work with 'C' batteries.

By the way, have you been able to get it to test for mAh real capacity with 'D' batteries?

http://imgmgr.banggood.com/images/upload/2014/04/Powerfocus%20BT-C3100%20OPERATING%20INSTRUCTIONS.pdf

The only difference between the OPUS BT-C3100 v2.2 and the OPUS BT-C3400 is the model number.

The BT-C3400 was “badged” for a particular dealer.

I remember reading this quite a while back here.

THIS is the only difference between the BT-C3100 v2.1 & BT-C3100 v2.2 / BT-C3400

And, to advance this discussion to the reported v3.1, this is the difference:

This is a customer made model. We changed some function like voltage for termination is changed to voltage with load condition, and discharge termination voltage is changed to a higher level to prevent charger from triggering protection for cells with protection.

This is a customer tailor made model.

Hi,

BTW, the BT C3100 V2.2 price is showing as $31.39 now when you select ship from the US-LA warehouse to US.

Healthy Guy

I am guessing by your username that you are into eating right.
As you already know I’m sure, you can’t always believe what’s inside the package no matter what it says on the outside. :wink:

OK, I just had a little fun.

One legitimate concern could be that if one tries to charge a “C” or “D” cell that has too high of a capacity, the delta V voltage may be missed by the hardware. In order to detect the delta V, the recommended charging current for NiMH cells is approximately 1/2 C where C is the mAh capacity.
The OPUS will charge at a maximum of 2000 mA if only the 2 outer banks. Perhaps charging a 10,000 mAh “C” cell at 2000 mA is too low to enable the OPUS to detect the delta V point. I would assume there would be a secondary point of shutdown, perhaps as simple as a maximum measured voltage across the cell.

That’s a great price. If I hadn’t recently bought Lii-500, I would have jumped on this deal.



Good observation! Yes, I'm a health food nut, but usually people think that I'm an obese junk food junkie who loves big buffets. ;)

On another note, do you think the Opus BT-C3400 will give correct mAh results for NiMH 5000 mAh batteries in the test mode?

Yeah, I couldn’t resist, and finally bought one of these guys :)!

Except there are no true 10,000mAh NiMH C cells.

There probably was a time, well over a decade ago, when Delta -V charge termination required 1/2 C charge rate with some cell and charger combinations, but for any decent modern charger, and after battery capacity went up too, that’s rarely if ever the case. Most can detect fine at 1/4 C and some, lower still. I doubt you could even find one today that can’t do 1/3C unless it was just a defective design, some generic clone/garbage/whatever.

Consider 2600mAh NiMH AA cells. How many people are using 1300mA rate capable chargers outside of flashlight junkies and the R/C crowd? They really shouldn’t even if they could as cell impedance may be higher to achieve the higher capacity in the same cell form factor. A charger capable of 1300mA ought to have a cell temp shutdown sensor and might end up using it.

FYI the Opus BT-C3100 is currently on sale at Gearbest for $26.61, but recently sold out.

You might want to check back later to see if more stock comes before the sale is over:

http://www.gearbest.com/chargers/pp_173012.html?wid=8&utm_campaign=404255

Hello everyone,

This is Thomas and I just registered, as I will need your valuable help for an issue that I have a BT-C3100 unit.
I bought it 1 year ago from Chinese reseller everbuying, after I had seen all the good reviews about this model.
I am charging mainly AAA batteries and it was doing its job quite good, until a few weeks ago.

Suddenly the unit started behaving really funny. Sometimes, even if there were 1-2 batteries inside the slots, the readings were not working properly and were showing null after a few minutes.
Or other times, the screen was stopping responding at the buttons, when I was trying to change the screen readings.
Also, the fan is not moving any more. I don’t remember if it should start working since the first second that you enter a battery for charging or it starts after a few minutes though.

I have read most of the other comments and I couldn’t find any similar behavior, which is really strange. And I don’t know what to think about these problems. Is the unit faulty or maybe there is an issue with the power supply, although the screen never stopped being on so far.

Any ideas about what to check or to do?

I dont have any help for most of your problems but one of mine became very noisy and the fan was “sticking”. I took it apart in a matter of minutes and gave the fan a good whack and it’s working fine again now.

I’m tempted to put a better fan on mine as the fan really is noisy and annoying!





GearBest is the worst company I have ever dealt with. A better name for this company is GearWorst. If I had known they were a Chinese company before I ordered, I would have never ordered from them, but they fooled me by offering me PayPal for my payment. Chinese company policies are very different than US company policies. They don’t care about their customers in China. They just want your money.



This is nothing more than a scam company. After sending me an $85 defective XTAR Dragon Plus charger, they said I could keep the defective item and they would refund me $15. WTF, and here’s the punchline. They will only refund me credit to be used when I buy another item. My refund goes into my GB Wallet. Who in their right mind treats their customers like this? I’ll tell you who. Scam companies in China!



I will never do business with GearBest again. I went to a GearBest review site and found hundreds of similar complaints about this company. Don’t believe the fake positive reviews or the employees. They are lying. I wish you the best of luck should you choose to do business with this scam company.



https://gearbest.pissedconsumer.com/

Try another 12V power supply.

Fans issues are known with this unit they give out eventually and it has thermal shutdown if it gets to 60c inside it cuts current not much higher the system shuts down until it cools enough. With your fan not working might be something thermal GearBest sells replacement fans for under $2 I bought a couple a week or so ago just to have on hand. To me its s great charger even if I have to change a fan occasionally no big deal takes 5-10 minutes

^ A multimeter could be handy right about now. Viper could check the input voltage from the PSU, and check whether there’s power getting to the fan header. No sense in replacing a fan if there’s no power getting to it. I mean yeah it is handy to have a spare, might as well order one considering the price and time it takes to ship, but usually you can just take your finger and see how the old fan is rotating…

If it’s giving some resistance or wobbling then it’s time to lube it. If wobbling, it was overdue to be lubed and you’re going to need a thicker goop to pump out less and make up for the play in the bearing (bushing). Personally, I mix 0W-20 or 5W20 synthetic oil with standard automotive lithium grease to salvage badly worn fans, till it’s just thin enough to flow.

Everyone has their own philosophy about lubing fans but there is some science and reason behind this. If your fan wasn’t worn you would want a thin oil, that is absorbed through capillary action into the bronze bushing. Once it is worn it most likely has an elliptical wear pattern and a thicker film strength is useful to reduce wobble and resultant lubricant pump-out, but with a thin base oil so it can still seep into the bushing better.

I’ve gone steps further in some cases to include a felt pad for a reservoir or a plastic backing sealed with epoxy to provide a lube reservoir, but in this case the fan is so small and inexpensive that the effort may not be worth the bother to do more than a basic lube.